Multiple piezo-electric transformer



June 14, 1932. A, MCL, NICOLS N 7 1,863,345

MULTIPLE PIEZO ELECTRIC TRANSFORMER Filed March 11, 1927 2 Sheets-Sheet l v HMP.

INVENTOR ALEXANDER McLEAN NICOLSON ATTORNEY June 14, 1932. AHM L. NICOLSON MULTIPLE PIEZO ELECTRIC TRANSFORMER 2 Sheets-Sheet 2 Filed March 11. 1927 HMP.

Fig.5

Rig. 6

INVENTOR ALEXANDER McLEAN NlCOLSON & Z W ATTORNEY Patented June 14, 1932 UNITED STATES PATENT OFFICE MCLEAN NICOLSON, OF NEW YORK, N. Y., ASSIGNOR, BY MESNE ASSIGN- MENTS, TO WIRED RADIO, INCL, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE i MULTIPLE PIEZO-ELECTR-IC TRANSFORMER Application filed March 11, 1927. Serial No. 174,488.

This invention relates to piezo-electric crystal devices, and more particularly to such devices adapted to be used as transformers and particularly adapted to be used for coupling thermionic relays to other devices or to each otheryand more particularly, relates to improvements on the arrangements described and claimed in my copending application entitled Piezo-electric coupling, Serial No. 155,896, filed Dec. th, 1926, and my Patent No. 1,829,234 of October 27, 1931, entitled Piezo-electric transformers.

It is an object of this invention to provide piezo-electric apparatus which will afford, with respect to electromotive forces or currents impressed upon the input or motor apparatus, and derived from the output, or generator apparatus, not only the desired ratio between potentials or currents, but will afford also, different resonant conditions in the different devices and different phasing of eleetromotive forces and resulting currents, whereby crystal devices having various characteristics may be associated in operation to produce various desired effects such for instance as a transformer having a fiatresponse characteristic over a certain range of frequencies.

It is a further object of this invention to provide piezo-electric apparatus comprising a plurality of piezo-electric crystal devices, associated together in various ways for op eration to produce the desired output characteristics, particularly adapted for coupling thermionic relays to other devices, or to each other. 1

It is still a further object of this invention to provide a thermionic relay system utilizing a plurality of thermionic relays coupled in cascade, in which the coupling means comprises a piezo-c'lectric crystal system, having .the desired characteristics. Still other objects of this invention will be apparent from the specification.

The features of novelty which I believe to be characteristic of. my invention are set forth with particularity in the appended claims. My invention, itself, however, both as to its fundamental principles and as to its practical embodiments will best be under;

filed Dec. 20, 1926, and Piezoelectric transformers, Serial No. 163,325, filed J an. 25th,

1927, I have shown and described arrangements for coupling circuits by means of piezoelectric elements and more particularly in the latter application I have shown and described an arrangement which I term a piezoelectric transformer utilizing a piezo-electric motor crystal driven by electrical oscillations in one circuit and producing mechanical stresses thereby. The mechanical stresses are impressed upon a second pieZo-electric crystal forming a generator element and the electrical oscillations resulting from the mechanical stresses applied thereto, are utilized to initiate or control the oscillations in the circuit desired.

In accordance with this invention, I have provided arrangements for controlling the energy transfer characteristics of a piezoelectric transformer in order to obtain any desired characteristics.

In accordance with this invention, I may utilize a plurality of crystal devices associating electrically in any desired manner with a source of electrical oscillations and operated thereby to produce mechanical stresses. The mechanical stresses may be applied to a plurality of generator crystals which are linked together electrically, and the characteristics of t-he individual crystals, either motor or generator, and the association, either electrical or mechanical, may be so chosen as to afford the desired over-all characteristics. For example: The motor crystals may be electrically connected either in series or in parallel, and they may be either mechanically associated or insolated; likewise, the generator crystals may be so arranged. Furthermore, the crystals may be arranged mechanically either in series or in parallel, or in what I may term horizontal or vertical chains. In any event, it will be seen that a wide range of characteristics may be obtained by the proper selection of one or more of all of the variable factors as pointed out above.

Referring now more particular to Fig. 1, I have shown an arrangement utilizing one form of piezo-electric transformer for cou pling thermionic relays. In this figure, S represents a source of electrical oscillations. 1. 2 and 3 designate piezo-electric crystal motor elements. such for example as crystals of Rochelle salt exhibiting the hour glass configuration, and provided with electrodes 1 d 5, 6 and 7, and 8 and 9, respectively. '1 he electrodes may take any desired form, such for example as an internal electrode formed within the crystal, and an external electrode applied thereto, or a pair of enternal electrodes applied at opposite electrical poles, or in fact, any desired arrangement .useful for the puriose. Electrodes 5 and 6 are connected together as are electrodes 7 and 8, and electrodes 1 and 9 are connected to a source of electrical oscillations such for example as the output circuit for a thermionic relay or other circuit affording electrical oscillations which it is desired to impress upon the thermionic amplifier 26. A plurality of piezo-electric crystal generator elements are provided such as 10. 11. 12. 13 and id. having electrodes 16 and 17. 18 and 19, 20 and 21, 22 and 23. and 24 and 25 respectively.

The electrode 16 may be connected to the grid or control electrode 27 of the thermionic relay 26 having a filamentary cathode 28 adapted to be heated by a suitable source of" energy such as filament battery 30. The electrode 25 may be connected to the filament circuit. A series connection may be made between electrodes 17 and 18, 19 and 20, 21 and 22, and 23 and 24, as shown, whereupon as will be apparent, the input circuit of the thermionic relay 26 will include crystal devices 10. 11, 12, 13 and 14-, in series. The output ircuit of thermionic relay26 comprising anode 29 and a suitable source of potential 31, may include a similar pieZo-electric transformer system 32, the secondary of which is connected in the input circuit of the thermionic relay 33 by means of a connection to the grid or control electrode 34 and to the filament 35, and the output circuit of which may comprise the anode 36, a suitable indicating instrument which may be a pair of telephone receivers 39, and the usual battery or other source of potential 37.

It will be noted in this instance, the motor cr' stals 1, 2 and 3 are mechanically associated with each other and are electrically connected in series. It will also be observed that gen erator crystal devices 10 and 11 are mechanically associated directly with motor crystal 1 but indirectly with the crystals 2 and 3, as a result of the mechanical connection between all of the motor crystals.

It will be understood that the phase of operation of any one of the crystals may be reversed by reversing the c'onnectionsto the electrodes and it will also be understood that he amplitude and frequency characteristics of the individual crystals may be controlled by the mechanical association between the crystals; for example, application or stresses to the crystal 10 at adifferent point from that shown, may result in the vibration of the crystal device 10in a different mode and at a different frequency or frequencies.

Referring now more particularly to Fig. 2, Ihave shown a source of electrical oscillations S, the motor crystals 1, 2 and 3, as electrically connected in parallel instead of in series, and free mechanically with respect to each other, and likewise associated in a different manner with respect to the generator crystals 10, 11, and 12. It will be understood, however, that if desired, any one of the crystals 1, 2 and 3 may be mechanically associated with another, and the association of the generator crystal or crystals with their respective motor crystals may be changed as desired.

Referring now to Fig. 3, I have shown still a different arrangement in which the motor crystals 1, 2 and 3 are connected to the source of electrical oscillations S as in Fig. 2 but in which the generator crystals 10, 11 and 12 are mechanically associated with the motor crystals in still a different manner, and are coupled inductively to the input circuit of the amplifier system 26 by means of coils 45, 416 and 47 respectively, connected between electrodes 16 and 17, 18 and 19, and 20 and 21: Each of these coils is inductively coupled to coil 48, 49 and 50 respectively, which are connected in series or in parallel if desired, and to the input circuit of the amplifier system 26.

Referring now more particularly to Fig. 1, I have shown a system similar to that shown in Fig. 2 except that the motor crystals 1. 2 and 3' are mechanically associated with each other as in Fig. 1. In this instance, however, a portion of the energy of the output circuit of the amplifier system which may comprise any number of stages as desired, is fed back into the input side of the motor crystals for the purpose of reinforcing. the oscillations insaid circuit to the'extent, if desired, of producing sustained oscillations.

Referring now more particularly to Fig. 5, I have shown an .arrangement in which there are provided not only motor crystals 1, 2 and 3, but additional motor'crystals 51, 52 and 53 having electrodes 54 and55, 56 and 57 and 58 and 59 respectively, mechanically associated in series with the crystals 1, 2 and 3 respectively, and forming what'I may term a vertical chain for operating the generator crystals 10. 11 and-12, whereas the arrangement shown in Fig.1, I term a horizontal chain. In this instance, all of the motor crystals are shown as electrically connected in parallel, but it is to beunderstood that any desired electrical connection may be provided. The mechanical association of motor crystals 51, 52 and 53 and generator crystals 10, 11 and 12 respectively, is similar to that shown in Fig. 3, but the circuit including these crystals is shown as coupled to the input circuit of the amplifier system by means of coils 60 and 61 inductively coupled to each other instead ofby a direct connection.

The output circuit of the amplifier may be connected to a suitable work circuit by means of coils 62 and 63' arranged in-inductive relation and a suitable amount of energy may be fed back to the input circuit of motor crystals 1, 2 and 3 by means of coil 64 in inductiveie lation with coils 62 and 63. By a suitable adjustment of the phase and intensity of the energy fed back, it will beundrstood that sustained oscillations may be produced in the system. It will be understood that by arrangements of the various crystal devices for particular modes of vibration and particular association with each other, asshown and de scribed in my application entitled Orientation of component crystalsin composite piezoelectric devices, Serial No. 155,902, filed Dec. 20, 1926, as well as by choice, of the nature and characteristics of the individual crystals and their electrical association with each other, it is possible-to provide a wide variation in the characteristics of the system.

Referring now more-particularly'to Fig. 6, I have shown still a'further arrangement which maybe utilized- In this figure, 7O designates a suitable source of electrical oscillations impressed upon the. input circuit of a thermionic relay 71 of the usual type,

associated with the motorcrystal 79, and a pair of motor crystals'85 and 86 are arranged trodes 93, 94, 95 and 96 respectively. In case the frequency characteristics of these crystals are different, tuning means 97 and 98 may be provided for maintaining a separation of the frequencies, if desired; and the output of the entire system may be impressed upon the input circuit of a suitable thermionic amplifying system 100.

It will be seen that in the arrangement shown, the stresses developed in the master mot-or crystal 79 are passed through the master generator crystal 82, the motor crystals 85 and 86 to the generator crystals 91 and 92, but it will be understood that if desired, the crystal 82 may be separated from the crystals 85 and 86, whereby he final. motor-generator systems will be electrically, but not mechanically, associated with the master motor generator system. As before, by solecting or controlling the characteristics of the individual crystals and the manner of theirassociation, both electrical and mechanical, it is possible to obtain Widely different output characteristics.

hile I have shown and described certain preferred arrangements of the apparatus according to my invention, it will be understood that modifications and changes may be made'without departing from the spirit and scope of my invention as will be understood by those skilled in the art.

I claim:

1. A piezo-electric transformer comprisin a piezo-electric crystal device upon which an electromotive force of certain characteristics may be impressed, means for impressing said electromotive force thereon, a plurality of other piezo-electric crystal devices each having a frequency characteristic different from the others mechanically associated with the first said crystal device, and means to de rive an electromotive force of characteristics different from the first said electromotive force as a composite output from the last said crystal devices.

2. A piezo-electric. transformer ystem comprising in combination a plurality of pieZo-electric transformers having frequency characteristics different from one another, each comprising a piezoelectric crystal motor element, and a piezo-electric crystal generator element mechanically driven thereby,

electrical connections between the motor crystals of each transformer, means for impressing actuating forces on said motor crystals, and means for integrating the effects thereof in said piezo electric crystal generator elements.

3. A piezo-electric transformer system comprising in combination a plurality of piezoelectric transformers, each transformer having a frequency characteristic peculiar to itself and comprising a piezo-electric crystal motor element and a plurality of piezo-electric crystal generator elements driven thereby, and electrical connections between the generator crystals of each transformer for integrating the effects of said motor element upon each of said generator crystals.

a. A piezo-electric transformer system comprising in combination a plurality of piezo-electric transformers having frequency characteristics different from one another, each transformer comprising a piezo-electric crystal. motor element and a piezo-electric crystal generator element, and electrical connections between the motor crystals of each transformer and between the generator crystals of each transformer for integrating the effects of said generator'crystals in accordance with the operation of said motor crystals.

5. A piezo-electric transformer system, comprising in combination a plurality of piezo-electric transformers, each transformer comprising a piezo-electric crystal motor element and a piezo-electric crystal generator element driven thereby, and electrical connections establishing a series circuit through the generator crystals of each transformer.

6. A piezo-electric transformer system comprising in combination a plurality of piezo-electric transformers, each transformer comprising a piezo-electric crystal motor element and a piezo-electric crystal generator element driven thereby,'and connections establishing a parallel circuit through the motor crystals of each transformer. a

7. A piezo-electric transformer comprising in combination a piezoelectric crystal device. means for impressing electromotive forces thereon. and a plurality of piezo-electric crystal devices associated with said first device in a manner to be stressed by vibrations thereof, said piezo-electric crystal dcvices'having differing characteristics. a circuit including said first mentioned piezoelectric crystal device and an independent circuit including said plurality of piezo-electric crystal devices.

8. A piezo-electric transformer system, comprising in combination a plurality of piezo-electric transformers, each transformer comprising a piezo-electric crystal motor element and a piezo-electric crystal generator element driven thereby, and electrical connections between corresponding crystals of each transformer, said crystals having different frequency characteristics and operating to receive variable electrical currents at each motor element and modify the effect thereof at each generator element.

9. A piezo-electric transformer system comprising in combination a plurality of tics, each transformer comprising a piezo electric crystal motor element and a piezo electric crystal generator element driven therebya-nd electrical connections establishing a parallel circuit through the generator crystals of each transformer.

11. A piezo electric transformer system comprising a plurality of piezo electric transformers having different frequency characteristics respectively, each transformer comprising a piezo electric crystal motor element and a piezo electric crystal generator element driven thereby and connections establishing a series circuit through the motor crystals of the several transformers.

12. A thermionic system comprising a plurality of thermionic relays, means for coupling said relays comprising a piezo electric transformer system including a plurality of groups of electro-mechanically associated piezo electric crystals each group having its own frequency characteristic, one of the crystals of each group being a motor crystal, the other crystal of each group being a generator crystal, the motor crystals being connected in the output circuit of one of the said thermionic relays, and the generator crystals being connected in the input circuit ofthe other of the said thermionic relays whereby the last said relay is provided with a flat response characteristic over a given range of frequencies.

13. A thermionic system comprising a plurality of thermionic relays, means for coupling said relays in cascade comprising a piezo electric transformer system including a plurality of piezo electric motor and generator elements composed of electro-mechanical- 1y associated crystals having differing frequency characteristics, means for delivering energy from one of said relays to the motor crystals of said transformer system, and

means for delivering energy from the generator crystals to the control circuit of the other of said relays, said delivered energy having a frequency characteristic which is the resultant of the frequency characteristics of the several pairs-of motor and generator crystals.

Signed at New York city in the county of New York and State of New York this tenth (lay of March, A. D., 1927.

ALEXANDER MOLEAN NICOLSON. 

